• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.527-536
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• 2009

A potent protein degrading bacterium was isolated from soil samples of different environments. Polyphasic taxonomic studies and phylogenetic 16S rRNA sequence analyses led to identify the isolate IB No. 11 as a strain of Bacillus subtilis. The isolated strain was recognized to produce protease constitutively, and the maximum production (1.64 units/ml) was attained in a shake flask culture when the isolate was grown at $40^{\circ}C$, for 32 h in basal medium supplemented with starch (0.25%) and gelatin (1.25%) as sole carbon and nitrogen source, respectively. The optimum pH and temperature for the protease activity were determined to be pH 7.0 and $50^{\circ}C$, respectively. $Ca^{2+}$ and $Mn^{2+}$ enhanced remarkably the protease activity but neither showed positive effect on the protease's thermal stability. In addition, it was observed that the protease was fairly stable in the pH range of 6.5-8.0 and at temperatures below $50^{\circ}C$, and it could be a good candidate for an animal feed additive. The inhibition profile of the protease by various inhibitors indicated that the enzyme is a member of serine-proteases. A combination of UV irradiation and NTG mutagenesis allowed to develop a protease hyper-producing mutant strain coded as IB No. 11-4. This mutant strain produced approximately 3.23-fold higher protease activity (6.74 units/mg) than the parent strain IB No. 11 when grown at $40^{\circ}C$ for 32h in the production medium. The protease production profile of the selected mutants was also confirmed by the zymography analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.396-402
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• 1996

This study was conducted to determine the effect of treatment with the plant-growth-promoting bacteria on the growth and yield of red pepper(Capsicum annuum L.) with different soil electrical conductivity(EC) levels. The mixed liquid culture was done pseudomonas P and saboraud dextrose medium. The isolated bacteria(IB) were inoculated by spray of 3.7ml at 1/2000a pot filled with different soil electrical conductivity level(2.9, 8.6, 11.5dS/m) every week, respectively, with mixed liquid culture (Pseudomonas P+Sabouraud dextrose) of eight strains. The plant height of red pepper with IBs treatment in different soil EC levels showed better growth than IBs nontreatment in the order of the 2.9>8.6>11.5 dS/m. The yield of pepper with IBs treatment in different soil EC level was higher in 13% than IBs nontreatment and chemical properties($P_2O_5$, K, Ca, Mg) of the soil after harvest in IBs treatment were slightly increased, while organic matter and EC of IBs treatment were slightly decreased than those of IBs nontreatment. Moisture content of the soil after the harvesting with IBs treatment was slightly increased than IBs nontreatment.